The game requires the player to navigate labyrinthine mines while fighting virus-infected robots. The player is given the clear objective to find and destroy each mine's reactor core and escape before the mine is destroyed by the meltdown. Occasionally, for some levels, the reactor core is replaced with a boss, changing the objective that the player must destroy the boss in order to trigger the meltdown and escape before the mine blows up. To obtain access to the reactor, the player must collect the blue, yellow, and/or red access keys for each level, which are required to open doors. As an optional objective, the player can also choose to rescue PTMC workers who were taken hostage by the infected robots.

Descent features a complementary points system. Players can score points by destroying enemy robots, picking up power-ups, and detonating the reactor. Bonus points are awarded upon completion of each level. These bonus points are based upon the player's shield and energy count, the skill level played, and a combination of picking up any hostages and safely rescuing them.

Descent demands that players keep their sense of orientation in a fully 3D environment with a flight model featuring six degrees of freedom in zero-gravity. Traditional FPS games require the player to only control two axes and their heading. By employing six degrees of movement, the player is given additional control for vertical movement and banking, introducing more movement controls than traditional FPS games. Descent‍ '​s unique movement controls also increase the possibility for players to experience motion sickness or nausea – a common complaint found in reviews for the game.[3][4]

The player is given the choice to natively use a keyboard, mouse, joystick, or combinations of these devices. Use of a second input device with or without a keyboard provides a greater amount of control due to the additional degrees of movement. The game also supports the use of two independently configured joysticks. One of its many supported input methods was mouselook, which at the time had not yet become standard in first person games. Since mouselook blew everything else away in multiplayer, it either became required to play multiplayer, or banned on some servers.[5]

Like Doom, Descent provides a navigational wire frame map that displays any area of the mine visited or seen by the player, which revolves around the player's position. Use of the slide controls (commonly the joystick "Hat" switch) allows the player to navigate to areas of the map away from their current location. The use of wire-frame models meant that areas at varying distances would appear to mix together when overlapping. This was overcome in Descent 3 with the use of opaque wall brushes and lighting closely matching that found in-game. Additionally, Descent 3's map system allowed the player the ability to move the viewpoint through the tunnels in map mode.

The primary weapons in Descent use energy, with the exception of the Vulcan cannon, which uses traditional ammunition. The player's spacecraft has a maximum energy capacity of 200 units; energy is replenished from energy power-ups floating in the mines or ejected by destroyed enemies. Energy can also be topped up (to a maximum of 100 units) at "energy centers," permanent recharge locations.

Descent uses shield power as health. As with energy, the ship "maxes out" at 200 shield units; unlike energy, shields can only be restored by acquiring "shield orb" power-ups. If the player finishes a level with shield power or energy power below 100 units, the ship will be recharged to 100 units for the next level.

When the player's ship is destroyed, all acquired power-ups and weapons are strewn about the area as power-ups, and, at a cost of a life, the player's ship is respawned at the original starting position. In multiplayer games, extra shield and energy pickups are also dropped upon death.

Descent offers competitive multiplayer game play for up to eight players over a LAN and is touted as being one of the first games to allow initiating sessions conveniently from a menu within the game as well as on-the-fly joining of multiplayer games, whereas in many similar games of the era, such as Doom, it is presumed that all players have to be queued prior to initiating the match.

Descent II was especially popular online due to its support for short packets and variable packet rate, which significantly improved quality of play over the slower Internet connections prevalent at the time.

The game begins with a briefing between a bald anonymous executive (in later games named Dravis) of the Post Terran Mining Corporation (PTMC) and the player, a "Material Defender" (revealed as MD1032 in the briefings, also using the callsign "Vertigo-1") hired on a mercenary basis to eliminate the threat of a mysterious computer virus infecting the machines and robots used for off-world mining operations. The game progresses through the Solar system, from the Moon to Mercury, then outbound towards Pluto's moon Charon. After defeating the boss robot on Charon, the Material Defender is informed he cannot return to the PTMC's headquarters in Earth orbit, as there is a chance his ship may be infected with the same virus as the defeated robots. His employer also mentions that PTMC has lost contact with their deep-space installations outside the Solar system, hinting at what is going to happen in the sequel.

The original Descent was developed by Parallax Software for DOS and PCs as platform. Like most games of its era, Descent was developed with a software renderer, because mainstream 3D graphics accelerator cards did not exist at the time. However, while most of its contemporaries—Doom included—use sprites, to render enemies, Descent renders enemies in full 3D using polygon meshes, a technique employed by Quake one year later. Sprites are used only for power-ups and the hostages. Descent'sgraphics engine uses portal rendering, taking advantage of the game's use of collections of cubes to form rooms and tunnels, in contrast with Doom and Quake, which use BSP trees. This system was very efficient, and made possible one of the first true 3D textured environments in a video game. On lower-end systems, detail levels could be reduced to cut out some of the smaller polygons on robots and render solid color blocks in place of textures on distant walls and across passageways in the distance. Within the game, sides of cubes can be attached to other cubes, or display up to two texture maps. Cubes can be deformed so long as they remain convex. To create effects like doors and see-through grating, walls could be placed at the connected sides of two cubes. The game also introduced an elaborate static lighting scheme alongside its simple dynamic lighting, where the environment could be lit with flares—another advancement compared to Doom. Descent II later added more dynamic lighting effects, including the ability to shoot out light fixtures. The original Descent uses indexed 8-bit color in DOS's display mode 13h with a 320 × 200 resolution. Unlike its sequel it uses only one 256-color set during gameplay rather than a unique set for each group of levels; these colors tinge red during damage and purple during fusion charging. The Macintosh and later PC versions allow higher resolutions, such as 640 × 480.

The default engine uses a software renderer in which the perspective transformation for texture mapping is only performed once every 32 pixels, causing textures to appear to pop or shift when viewed from certain angles. The software renderer also uses nearest-neighbor texture filtering, as opposed to bilinear filtering or trilinear filtering used by modern video cards. Nearest-neighbor texture filtering causes aliasing artifacts, such as blocky textures. These rendering compromises allowed the game to be played on most PCs contemporary with it, while better rendering techniques would have prevented it from being run on any but the most powerful gaming PCs in 1994. Due to the game's CPU burdening software rendering, the game was playable on 386 CPUs at 33 MHz and for good-quality rendering with full-screen view and better than minimal render depth, a 486 running at least 66 MHz was required. With the release of the faster Pentium, the performance requirements were no longer an issue and maximum rendering quality was possible.

Descent was originally released in Europe for MS-DOS in December 1994, and made it to North America on March 17, 1995. Initially it was released by Interplay as shareware, with the full version released three months later, just over a year after the December 1993 release of id Software's Doom. On that year came the Mac OS, Acorn Archimedes and PC-98 releases as well, respectively exclusive to North America, Europe and Japan.[7]

In 1995, a commercial Descentlevel editor called Descent Mission Builder, created by Bryan Aamot of Brainware was published by Interplay Productions.[citation needed] Users can create their own single-player and multi-player levels with the program and then play them. Later that same year came Descent: Levels of the World, a popular add-on containing all of the entries from a level design competition held by Interplay in 1995. A viewer is included, allowing the player to see a preview of each map, as well as selecting ones that received a "Top 10" award or an honorable mention.

A Sega 32X version of Descent was announced as the first console version,[8] but it was never released.

In 1996, Descent: Anniversary Edition was released on the one-year anniversary of the original game's debut. the Anniversary Edition featured Descent, the Levels Of The World add-on, and several additional levels created by Parallax.

A version of Descent was produced for the PlayStation in 1996. It features thirty levels, with five new anarchy levels, the remixed soundtrack from the Mac OS version (featuring Type O Negative and Nivek Ogre of Skinny Puppy), prerendered cinematics (using the same cinematic engine as Descent II), and radiosity colored lighting effects.

In 1997, Descent was bundled with its 1996 sequel Descent II in Descent 1 and 2 The Definitive Collection. This included Descent, the Levels Of The World add-on, and several additional levels created by Parallax. The various expansions for Descent II were also included, as was a preview of the upcoming Descent 3.

In February 1997, it was confirmed that Interplay was planning to release the game to the Nintendo 64 in time for the holiday season under the name "Ultra Descent", as it had done for the PlayStation the previous year.[9] Throughout the next two years it was said that the game was still in development and release dates were scattered all over the place until it was silently canceled in late 1999.[10][11]

In February 1996 Descent's official support ended with Parallax' last patch v1.5;[12] therefore the game runs fine on PCs' using Windows 95, but has compatiblity problems with the later released Windows XP.[13]

In 1997 on the commercial end of life the source code of the original Descent was released, excluding the audio code, which was later replaced with the Allegro library.[14] The source code to Descent II was subsequently released in 1999.[15] Parallax Software released the source code to the original Descent and Descent II under the terms of a non-free source code license[16] in which that all commercial or revenue-generating distribution is restricted.

Descent was a critical and commercial success. Gamespot gave the PC version an 8 out of 10, remarking that "Only one 3-D shooter adds a whole new dimension to the field: Descent." They particularly noted the labyrinthine environments and free three-dimensional range of movement.[27]

The four reviewers of Electronic Gaming Monthly called the PlayStation version an outstanding conversion due to its extremely fast rendering speed and improved lighting effects. However, two of them felt that the gameplay lacked excitement. They scored it a 7.375 out of 10.[28]GamePro also judged it "an excellent conversion" due to its complex but generally easy to master controls and impressive lighting effects, though they did complain of sometimes severe slowdown.[29]Maximum gave it four out of five stars, saying it "is one of the greatest games to grace the PlayStation, and rates alongside WipeOut as one of the best ambassadors for the machine." They particularly applauded the labyrinthine level design, intelligent enemy AI, and lighting effects.[30] Their subsequent feature on the game was more critical, saying that "the official PAL version of Descent features some of the most hideous letterbox PAL borders we've ever seen, with no sign of PAL optimisation whatsoever." However, it also praised the game's use of the PlayStation link up cable.[31]

In 1997, Interplay released Descent to Undermountain, an RPG that used a modified version of the Descent graphics engine, but that was otherwise unrelated as it took place in a medieval fantasy setting.

The popularity of Descent brought about several similar six-degrees-of-freedom shooters. Perhaps the most well-known "Descent clone" was Forsaken, which was released in 1998 for PC, PlayStation, and Nintendo 64. Forsaken had similar graphics to Descent, and almost identical gameplay.[33]

Descent: FreeSpace – The Great War was released by Volition, Inc. in 1998. It shared the Descent name, but otherwise had no connection to the series; it was given the "Descent" prefix to avoid trademark issues[34] (in Europe, it was released as Conflict: FreeSpace – The Great War). FreeSpace was a space simulator, and while it was still technically a 3D shooter, it did not retain Descent‍ '​s characteristic "six degrees of freedom" control scheme, save for a cheat code that would force the player's ship to loosely mimic Descent‍ '​s physics. Some early drafts of the FreeSpace story had the pilot searching for Descent‍ '​s "Material Defender"[citation needed], but the story of the finished game was unrelated.

Around that time, Volition also began work on Descent 4, but development was canceled in 2000, owing mostly to disappointing sales of Descent 3.[citation needed]Descent 4 may have been originally planned as a prequel to Descent, and reportedly served as a basis for the first-person shooter Red Faction. Similarities include a reference to a "humans first" strike in Descent‍ '​s opening briefing, and plot points such as nanotechnology, an evil faceless corporation, and the virus they are attempting to harness. Mike Kulas (president of Volition) stated in an interview that the Red Faction and Descent universes are strictly separate, however he did admit that code intended for Descent 4 had been used in Red Faction.[35]

Miner Wars 2081, a six degrees of freedom game released in 2012, features audio work by Dan Wentz, sound effects editor for Descent II.

In 1999 the Descent series also spawned a trilogy of novels written by Peter Telep and sold at several major booksellers.[36] The titles are Descent, Descent: Stealing Thunder, and Descent: Equinox. The novels did not follow the games to the word, but expanded on the basic premise, and were very well received.[citation needed]

In November 2014, several former developers for the Star Citizen game, led by Eric "Wingman" Peterson announced that they were forming Descendent Studios to work on a multiplayer game similar to Descent in play style, and with the working title "Ships That Fight Underground".[37][38] The company was approached by Interplay in December and a deal was stuck to license the Descent name to Descendent Studios.

In March 2015, Descendent Studios announced a kickstarter for Descent: Underground, a new prequel using Interplay's existing IP rights to the Descent franchise (with Volition owning the remaining properties, such as the original "Pyro GX" ship and music).[39] It is powered by Unreal Engine 4 and has a planned release date of March 2016.[40][41]

^Dunkin, Alan (1998-01-26). "Descent Source Code Released". gamespot.com. Retrieved 2013-01-13. Parallax Software, the software developer that created the popular three-dimensional action games Descent and Descent II, has released Descent's source code (version 1.5) to the public domain for noncommercial purposes.